"There is, however, no such thing as natural law and a perennial
standard of what is just and what is unjust. Nature is alien to the idea
of right and wrong. "Thou shalt not kill" is certainly not part of
natural law. The characteristic feature of natural conditions is that
one animal is intent upon killing other animals and that many species
cannot preserve their own life except by killing others. The notion of
right and wrong is a human device, a utilitarian precept designed to
make social cooperation under the division of labor possible."

---

"From the notion of natural law some people deduce the justice of
the institution of private property in the means of production. Other
people resort to natural law for the justification of the abolition of
private property in the means of production. As the idea of natural
law is quite arbitrary, such discussions are not open to settlement."

"Traditionally, the champions of democracy had defended thispolitical form with the help of arguments rooted in ethics ornatural law. All men are born equal, they claimed, and thereforeall men should be equally involved in political decision-making.But this could only be realized in a democracy. Mises did notfind this line of reasoning convincing. He believed it was ratherobvious that all men were born unequal, and he had littlepatience with arguments based on claims about natural law,which he considered to be a fiction of the intellect. No agreementcould ever be reached on a fiction. Rather, it was to beexpected that everybody made up his own version of “natural”law, to buttress his political agenda. Thus natural-law considerationswere simply unfit to be applied in politics, because thevery point of politics was, from Mises’s perspective at any rate,to resolve conflicts."

If the natural rights theory is used to justify equal say in political decision-making, I would agree, but because I think majoritarian democracy is coercive with respect to the dissenters. However, I have always thought of natural rights theory differently, namely, to say that all men are born equal, in the sense of being born into the same species, and thus no man has any natural right to rule over another. Put differently, if all men are born into the same species, then one cannot justify a rule which does not apply equally to all men. And the only rule which can in practice apply equally to all men is a negative rights philosophy, such as, no man may violate another's property.

Humans differ from animals that in that they rely on reason and the virtue of rational productivity to survive. Force is antithetical to reason and rationality, hence, rights are a natural requirement of human existence, qua man. I'm with Ayn Rand on this.